PALO ALTO — As if Theranos’ embattled founder and Chief Executive Elizabeth Holmes wasn’t in many people’s sights for the wrong reasons already, she now has almost 100 million more reasons to be worried.

That’s because Theranos investor Partner Fund Management (PFM) has sued the troubled blood-testing technology company claiming Theranos lied to PFM about the viability of its products in an effort to wring a nearly $100 million investment out of the San Francisco-based hedge fund.

var _ndnq = _ndnq || []; _ndnq.push([’embed’]);

PFM filed the suit in the Delaware Court of Chancery on Monday. In a letter that PFM sent to its own investors, and obtained by this newspaper, PFM says that Theranos engaged in “a series of lies, material misstatement, and omissions” as well as “securities fraud and other violations” that were meant to get PFM to invest and maintain its investment in Theranos.

Partner made a $96.1 million investment in Theranos in February 2014, and the hedge fund is seeking to recover damages exceeding its investment amount. In its suit, Partner says that Holmes, and Theranos’ former chief operating officer, Sunny Balwani, defrauded the hedge fund as they claimed the company’s technology was capable of doing far more tests than were possible.

“Theranos and its principals knowingly and repeatedly lied that they had developed proprietary technologies that worked, were on the cusp of receiving all necessary regulatory clearances and approvals, and concealed the truth about the commercial viability of their technologies and methods,” said a PFM spokesman in a statement. “Our responsibility to act in the best interests of our investors is paramount and we are resolute in our determination to fiercely protect and preserve their rights and remedies.”

Partner, founded 12 years ago, has more than $4 billion under management and mostly makes investments in publicly traded companies.

In a statement posted on its company website, Theranos countered PFM’s claims, calling the lawsuit “without merit” and its assertions “baseless.”

“Most of the company statements the plaintiff has cited in its suit were made after the time the plaintiff invested, and could not possibly have been the original basis for investment,” Theranos said. “This wholesale reliance on post-investment statements, therefore, negates the claim that the plaintiff was misled.”

Theranos didn’t return a request for further comment on the lawsuit.

Theranos, and its one-time wunderkind founder, Holmes, have been under fire for months over the veracity of claims associated with the company’s blood-testing technology.

Founded by Holmes in 2003, Theranos bolted onto the scene in Silicon Valley in 2013 shortly after the company made public what it claimed was a revolutionary method of blood testing. Theranos said that it could use only a few drops of a person’s blood, as opposed to the drawing of multiple test tubes of blood, to run dozens of accurate tests. As a result, investors such as PFM poured up to $800 million into Theranos, giving it a valuation of $9 billion by mid-2014.

However, the wheels began to fall off of Theranos’ claims following a 2015 Wall Street Journal investigation into the company’s technologies and practices. The Journal found that Theranos had used its technology for far fewer tests than it had reported, and used equipment from other testing companies to complete many of its tests. Last year, Theranos also ceased using its much ballyhooed Edison blood-testing system after disclosures showed the technology had only been used for a few dozen tests, a move that called into question the quality of results coming from Theranos’ testing facilities.

By mid-2016, thousands of Theranos test results had been declared invalid, and federal regulators revoked the company’s blood-testing license at a lab in California. In June, drugstore chain Walgreens pulled the plug on a partnership that involved Theranos machines being used at stores in greater Phoenix, and Holmes has been banned from running medical labs for at least two years, pending an appeal of that ruling. Theranos has said it will move away from blood testing to developing technology that will lower the costs of blood tests and make such tests more accessible to individuals.

Rex Crum is the senior web editor for the business section for The Mercury News and Bay Area News Group. He also writes about business and technology for the publications' print and web editions, and has covered business and technology for nearly two decades. A native of Seattle, he remains a diehard Seahawks and Mariners fan and is imparting his fandom to his Oakland-native wife and two young daughters.

When you’re Apple’s VP for diversity and inclusion and you make public comments that seem to downplay the importance of advocating for underrepresented groups in the workplace, you’re going to get blowback.